Usage of modems

The ASCII protocol considers the special properties of modems, interface converters and repeaters. If these devices are used at a serial interface operated in ‘free mode’, the compression mechanism possibly supported by these devices has to be deactivated. For detailed information, refer to the operation manual of the used device.

Some repeaters, modems or interface converters require a control signal in order to set the transfer direction. The direction control can be enabled or disabled via the input RTSCTRL.

Various devices additionally require a lead time to stabilize their carrier signal. These devices can only transfer data in send direction after this time has elapsed. This carrier lead time can be set via the input TLS.

Additionally, for some devices it is necessary to sustain the carrier signal in send direction for some time after data transfer is completed. Only if this time has elapsed, the complete transfer of a telegram is ensured and the devices are ready for data transfer in opposite direction. This carrier delay time can be set via the input CDLY.

Note

Carrier lead time (TLS) and carrier delay time (CDLY) must be adjusted for all communication devices connected to the same transmission line.

The times are only considered for RTS control set to telegram.

Note

For CI504-PNIO and CI506-PNIO: For the time settings of TLS/CDLY, the used baudrate listed in the following table has to be considered:

Baudrate [Bd]	Max. value for TLS/CDLY [ms]
300	850
1200	212
2400	106
4800	53
9600	26
14400	17
19200	13
38400	6
57600	4
115200	2